I have combat music playing in Balmora's waterfront for ingame weeks, the guards react to some presence, yet I have TCLed through everything to find this bandit. RA doesn't restore any bandit positions. Is there a console command that identifies hostiles or change the hostility state of Balmora?

You are sure it's not a cliffracer?

Guards only attack creatures. You can use a Detect Animal spell, potion, or enchantment to determine its location.

I have Passive Wildlife, Protective Guards and MCA 8.1 with bandits in town turned on. It is after the last bandit raid in Balmora that the music remains in combat mode. There are no visible npcs frozen in place, no one in the water. I TCLed throughout Balmora from below to see if a hostile had glitched through the terrain, nothing. Is there an ingame spell that cause villains to show up on the map or a console command that finds all npcs?

Any possibility that a Slaughterfish ended further upstream than usual? I've seen guards react to hostile fish on numerous occasions, and charge into the water after them. If there's no easy way to get there with the existing pathfinding, the combat music can play for days until the slaughterfish respawns elsewhere.